Is There Enhanced Evaporation In Surface-Exposed Fractures Due To Convection Of Water Vapor?
Academic Article

Overview

Research

View All

Overview

abstract

Diffusive fluxes limit the potential amount of evaporation from surface-exposed fractures and
other discontinuities crossing the land surface. However, if density differences between the
air above a fracture and the moist air within the fracture voids exist, convective flux might be
developed. If so, evaporation could increase by up to several orders of magnitude,
dependent on temperature differences and the size of the aperture. Theoretical calculations
suggest that under typical high deserts conditions convection is likely to occur during the
night while diffusion is likely to control evaporation from fractures during the day. Field
experiment carried out in the Negev desert of Israel showed that the amount of salts
accumulated within a fracture in six months is much higher than what could be explained by
diffusion alone. This further support the existence of additional mechanism that enhances …